Device for producing plates designed for a fast prototyping process, method for machining and assembling said plates and resulting plates and prototype workpieces

ABSTRACT

The invention concerns a device for producing plates made of metal, plastic or metallo-plastic composite material, whether they are non-exclusively thermofusible, thermoplastic or thermosetting designed more particularly to be machined with a machining tool in a fast prototyping process. The invention is characterised in that it consists of a plate mould integrated in the prototyping machine, said mould being adapted to receive a material matching the shape of the mould after being subjected to a heating/cooing cycle with heating/cooling means integrated in the mould body. It essentially comprises: a vat ( 2 ); a base plate ( 3 ); a heating circuit ( 4 ); a fluid circulation circuit ( 5 ).

[0001] The subject of the present invention is a device for producing plates made of metal, plastic or metallo-plastic composite, whether these being unlimitingly of thermofusible, thermoplastic or thermosetting type, intended more particularly to be machined by a machine tool in the context of a rapid prototyping process.

[0002] Another subject of the invention is a method for machining and assembling thermofusible plates for producing prototype parts, and the products thus obtained.

[0003] In general, reference will be made in the context of this application to the rapid prototyping process known by the name of STRATOCONCEPTION (registered trade mark) covered, in particular, by European patent EP 0 585 502B1 of which the applicant of this application is proprietor.

[0004] Reference will also be made to French patent applications 98 14687 and 98 14688 of which the applicant of this application is also the proprietor.

[0005] It will be recalled that the general STRATOCONCEPTION process consists in a process of producing mechanical parts and items, particularly prototypes, from a specific computer-aided design of the type comprising the successive phases of:

[0006] virtual breakdown into elementary laminates;

[0007] placement as a panoply;

[0008] manufacturing parts in elementary laminates or layers;

[0009] rebuilding all the layers;

[0010] assembling the layers

[0011] said laminates originating from a prior break-down of the part on predetermined planes and in one or more determined step(s).

[0012] The underlying principle consists in breaking down the volume that is to be reproduced in the form of a prototype into a multitude of laminates, produced by machining, for example rapid micromilling of a material in plate or sheet form, it being possible for example for said material to be made of wood, composite, plastic or metal.

[0013] Choosing the material from the above group necessarily involves a significant loss of material, something which is not in itself prohibitive in carrying out the process, but is nonetheless detrimental to the economy thereof, as the chips and offcuts of material and the milling residue produced cannot be used.

[0014] There is therefore a need for a machining process that allows the use of a material for machining the machine residue of which can be recycled as possibly can the machined parts themselves when they are of unsatisfactory quality or no longer have any use.

[0015] According to the invention, this result is obtained with a device for producing plates made of metal, plastic or metallo-plastic composite, whether they be, nonlimitingly, of thermofusible, thermoplastic or thermosetting type, intended more particularly to be machined by a machine tool in the context of a rapid prototyping process, characterized in that it consists of a plate mold incorporated into the prototyping machine, said mold being able to receive a material that hugs the shape of the mold having been subjected to a heating/cooling cycle by a heating/cooling means incorporated into the body of the mold.

[0016] The material used for implementing the above device may be in the form of a liquid, of granules or solid elements.

[0017] The material may be of the thermofusible type and may be a thermoplastic or thermoset.

[0018] In the case of the use of a thermoplastic, the heating/cooling process will be reversible.

[0019] In the case of the use of material in the form of granules, the cycle will include a phase of plasticizing by heat and compression or injection.

[0020] It will be understood that the invention finds an application for any material which can, within a reasonable temperature bracket, pass from the liquid state to the solid state, possibly reversibly.

[0021] According to an important feature of the invention, the machining of the plate constituting a laminate or a collection of laminates placed as a panoply will be performed directly in the mold, the chips thus generated being collected and possibly recycled, the part being held in the mold in the cold state and released therefrom by slight heating of its lower portion just enough to detach the plate from the bottom of the mold.

[0022] By comparison with the processes and devices of the prior art, the proposed device allows great ease of material supply.

[0023] On the other hand, it allows the automation of the overall prototyping process to be optimized.

[0024] The invention will be better understood with the aid of the description which follows with reference to the appended drawings in which:

[0025]FIG. 1 is a schematic view in part section of a device according to the invention, according to its basic principle,

[0026]FIG. 2 is an alternative form of the device of FIG. 1.

[0027] Reference will be made first of all to FIG. 1.

[0028] The device (1) according to the invention essentially comprises:

[0029] a tank (2)

[0030] a baseplate (3)

[0031] a heating circuit (4)

[0032] a fluid-circulation circuit (5).

[0033] The device (1) is fitted, for example by nuts (6, 7) onto a flat surface, for example the bed surface of a machine tool.

[0034] The bottom of the tank comprises a perforated plate (3) through which resistive heating elements (4) and a heating circuit (5) pass longitudinally.

[0035] The perforations (8) are made transversely in the plate and place the free face of the tank in communication with a lower reservoir of fluid (9).

[0036] The movement of the fluid is controlled by a piston (10) operating on compressed air or by any other mechanical system functionally equivalent and compatible with the conditions of use.

[0037] A retractable top plate (13) may temporarily close the mold while the material is being injected or during the curing phase.

[0038] According to alternative form of embodiment, it may be possible to get around the use of the plate (13) for closing the mold. In that case, the material will extend beyond the upper plane of the mold. Leveling will be performed by skimming, for example using the milling means already in place on the rapid prototyping station, or using any other scrapping method.

[0039] Excess liquid will be removed through vents (11, 12) placed for example in the upper part of the mold.

[0040] According to possible alternative forms of embodiment:

[0041] the cooling passages will also act as a network in which a heating fluid can be circulated,

[0042] the feed ducts may be situated only on the lateral parts of the mold in order to make the ducts easier to break off as the laminate is extracted.

[0043] The basic principle is the production of plates ejected, possibly be a suitable piston system, after cooling.

[0044] Numerous alternative forms of embodiment may be anticipated without departing the scope of the invention.

[0045] Thus, as depicted in FIG. 2, the retractable upper plate (13) allows the injection of a plate or part (14). Ejection is managed by a pneumatic and/or mechanical means (15) which will eject the part (14) after slight heating. The tank or the actual cavity of the mold will be considered to facilitate mold release and extraction of the part (14).

[0046] Use may just as easily be made of the plastic liquefied once again in the reservoir in order to eject the plate (14) which has remained solid. 

1. A device for producing plates made of metal, plastic or metallo-plastic composite, whether they be, nonlimitingly, of thermofusible, thermoplastic or thermosetting type, intended more particularly to be machined by a machine tool in the context of a rapid prototyping process, characterized in that it consists of a plate mold incorporated into the prototyping machine, said mold being able to receive a material that hugs the shape of the mold having been subjected to a heating/cooling cycle by a heating/cooling means incorporated into the body of the mold.
 2. The device as claimed in claim 1, characterized in that it essentially comprises: a tank (2) a baseplate (3) a heating circuit (4) a fluid-circulation circuit (5).
 3. The device as claimed in claim 2, characterized in that the bottom of the tank comprises a perforated plate (3) through which resistive heating elements (4) and a heating circuit (5) pass longitudinally.
 4. The device as claimed in either one of claims 2 and 3, characterized in that the perforations (8) are made transversely in the plate (3) and place the free face of the tank in communication with a lower reservoir of fluid (9).
 5. The device as claimed in any one of claims 2 to 4, characterized in that the movement of the fluid is controlled by a piston (10) or a pneumatic means (15).
 6. The device as claimed in any one of claims 1 to 5, characterized in that it comprises a retractable top plate (13) that temporarily closes the mold.
 7. A process for machining a plate constituting a laminate or in a collection of laminates placed as a panoply in the context of a rapid prototyping process by computer-aided breakdown into laminates, characterized in that the machining of the plate is performed directly in a mold as claimed in any one of claims 1 to
 6. 8. The process as claimed in claim 7, characterized in that the material used to produce the laminate is a metal, plastic or metallo-plastic composite which can change from a liquid phase to a solid phase.
 9. The process as claimed in claim 7, characterized in that the material used for producing the laminate is a thermoset or a thermoplastic.
 10. A prototype part, characterized in that it is obtained by implementing the process as claimed in any one of claims 7 to
 9. 